Magnetic amplifier circuit



W. T.' KEATING HAGNETIOAMPLIFIER CIRCUIT Jan. 14, 195s 2 Sheets-Sheet 1 Filed llareh 4, 1955 M N G 5 Jan. 14, 1 958 w. T. KEATING 2,820,191

MAGNETIC AMPLIFIER CIRCUIT Filed March 4, 1955 2 Sheets-Sheet 2 IN VEN TOR.'

Byzz/ Prn/ TTORNEY United States Patent MAGNETIC AMPLIFIER CIRCUIT William T. Keating, St. Albans, N. Y., assignor to Sperry Rand Corporation, a corporation of Delaware Application March 4, 1955, Serial No. 492,107

3 Claims. (Cl. 323-89) This invention relates to a magnetic ampliiier circuit which yields a full wave rectiiied current to the output being adapted to produce a differential in the load circuit the character of which depends on the type of signal control.

A primary object of the invention is to provide a magnetic ampliiier system which pulses the load on both half-cycles of a rectiiied line current.

The circuit is particularly adapted for operating a split winding motor requiring a differential to be placed on the windings. It could well be employed to produce operating diiterentials on control coils of a cascaded amplier system or to control the balance of a conventional bridge network. Another object is therefore to provide a magnetic amplifier system which produces a differential output on each half-cycle of line current.

The circuit employs four reactors with two reactors on each side of the load. Two reactors are disposed in each conducting half of the system and control the impedances in the load circuits for the two halves. The load circuits of each half have a common rectified return lead to the other side of the line. The impedance of the cores is in turn controlled by control windings in the signal circuit. The direction of the turns of the control windings is critical and depends on both the character of the signal and whether a D.C. or A.C. dilierential current in the load circuit is desired. Whether the signal current is alternating or direct, the control windings must be arranged in push-pull relation to the controlled flux in the reactors in the two conducting halves of the system to provide the desired differential in the windings. If an alternating current output is desired in the load circuit, the control windings must be arranged in push-pull relation to the reactors on each side of the load. The actual direction of the turns for producing the push-pull relation will depend on the character of the signal employed.

The invention will be further explained in connection with the embodiment illustrated in the drawings in which:

Fig. l is a. diagram of a magnetic amplifier circuit which produces a full wave rectiiied load current and a D.C. differential output for an A.C. signal or a differential A.C. output for a D.C. signal;

Fig. 2 is a diagram of a magnetic amplifier circuit which produces a full wave rectified load current and an A.C. differential output for an A.C. signal or a D.C. differential output for a D.C. signal; and

Fig. 3 is a diagram of a magnetic amplifier circuit having a D.C., split winding motor for a load.

Two pairs of reactors 10, 11 and 12 and 13 are connected in parallel across the alternating current lines 14 and 15. The reactors constitute closed magnetic circuits and have windings which are disposed on the cores in the usual manner.

Two branch circuits 16 and 17 are connected in parallel across lines 14 and 15 which are connected to a source ot alternating current. Each circuit has a pair of reactor windings 18, 19 and 20 and 21, respectively, which are 2,820,19l Patented Jan. 14, 1958 ice inductively related to core reactors 10, 11 and 12 and 13, respectively.

An output or load circuit 22 having split load impe'- dances 23 and 24 connects the branch circuits between their reactor windings at points a and b. Load 38 is connected between the same points. The split load impedances carry the entire current in the branch circuits, ine circuits being rectified to permit both half-cycles of line current to iiow across the load. To this end half wave rectiiiers 25 and 26 are provided in branch circuit 16 on each side of the load circuit connection a and are oppositely poled to permit the line current to ilow only in the direction of such connection. Similarly half wave rectiers 27 and 28 are provided in branch circuit 17 on each side of the load circuit connection b and are similarly poled for a unidirectional load current.

Leads 29 and 30 connect the load circuit 22 between the split load impedances 23 and 24 to the two sides 14 and 1S, respectively, of the line and in combination con` stitute a lead connection across the line in parallel with the branch circuits. Half wave rectiiiers 31 and 31a are provided in the leads 29 and 30, respectively, and are poled so as to furnish a return path for lthe unidirectional load current. The polarity of the rectiiiers in the leads 29 and 30 and the branch circuits 16 and 17 makes itapparent that the system is divided into two conducting halves. Lead 30 provides aline return for the current in the reactor windings 18 and 20 and lead 29 provides a return path for the current in reactor windings 19 and21. The core reactors 10 and 12 are in one conducting half being iluxed by the reactor windings in one half-cycle and reactors 11 and 13 are in the other conducting half-cycle being liuxed on the other half-cycle of line current. Reactors 12 and 13 are on one side of the load and reactors 10 and 11 on the other.

The impedance of the cores is controlled by signal circuit 32 which has control windings 33, 34, 35 and 36 disposed on reactors 10, 11, 12 and 13 respectively. The windings 33 and 35 are arranged in push-pull relation to the liux induced by the reactor windings on cores 10 and 12; similarly the windings 34 and 36 are in push-pull relation to the ilux induced by Ithe reactor windings in cores 11 and 13.

The control windings on each side of the load may be arranged in the same relation to the induced ilux or in push-pull relation thereto. Where they are in the same relation for either a D.C. or A.C. signal, either impedance 23 or 24 will carry more current than the other on both half-cycles. If the control windings are arranged for a D.C. signal, which pair of reactor windings will carry the higher current will depend on the polarity of the signal. Where the control windings on each side of the load are arranged in push-pull relation with respect to the flux induced by the reactor windings on the respective cores, the load current will in eifect be A.-C. with a higher current value in either impedance 23 or 24 every half cycle of line current.

It will be apparent that in Fig. 1 the control windings are wound so that the controlled and controlling flux bear the same directional relation to one another in the reactors on each side of the load for an A.C. signal, and that they are in push-pull relation for a D.C. signal. On the other hand in Fig. 2 the control windings are in the same relation to the reactors for a D.C. signal and are in push-pull relation to the reactors for an A.C. signal.

, A push-pull relation between the reactors on the same side of the load will cause a differential alternating load current with the two mpedances 23 and 24 alternately have ing high and low current values every cycle. If the reactors on each side of the load are brought to the same levels of saturation, one of the impedances will carry the Fhigher current on every half-cycle of linecrrnt-nd the other irripedarice"will"carry4 the lower current. Thesarne r1f MAC. signal' is" appned'tofjtne 'Signat ciruf in rig. t

trueion rhe-othersideff fhe'lauffr imp-eaM cei'zsl Xcj'pt su nalin cycles "whichjecunts fsf 'sie alternating-"current ensei Nacross' load 38.

"Iliatisjv the' controluxlis in pu'slilpull relatin'to `the *1 controlled' iix 'in 'cores' 12"'and 13 aswell" as inA tlicres 'onthe otherls'ide of the loz'tdfor'a D.`C. signal with the phase vof lthej` alternating currentin the lo'ad depending on the polarity ofthe signal. If the` signal'isAI-C. the saturation of the cores ist affected in the saine'sense nacliside of the load and the current is higher on one side than the other on both half-cycles of line current. `Wh`e`th"`er"irn 'pedance 23 or 24 carries the higher curientdependsonthe relative polarity of the'reactor Vand, 'control 'windings' on each core. Specically'reversingall fourcoiitrotwindl ings vas shown in Fig.y 1"`will reverse polarit'yof 'the load.

'-IIt" -isY understood" that the 'control "windrgsfhrithei two conducting halves of the system are wound in push-pull "relatin 'with respecttothe core Areactors on which Athey are wound. It is contemplated that the impedances require a current dilerential through them as would be the case were they solenoids or the control coils of a cascaded magnetic amplifier circuit, or the impedances of a split eld winding motor with'the armature 37 disposed, for example, as in Fig. 3.

Other modifications inthe circuitl willieadily o ccur to those s hiliedin the art withinutheprincipleiof"the Vinvention'as defined in the following claims:

What is claimed is:4

1. Ama'gnetic amplifier comprising'twopairsofclosed magnetic circuits, a reactor winding disposed on each magnetic circuit, an alternating current line, two branch circuits connected in parallel across the line, each branch circuit including in series two of said reactor windings, a load circuit connecting the two Ibranch circuits at points intermediatethe magnetic circuits in each branch, alpair o fhalf wave ree-tiers nthe branch circuits, one rectifier ybeingdisposedl on each side of the load circuit connections and pold in the direction of said connections, a signal circuithaying a control winding disposedon each magnetic circuit,` thesaid control windings in'each conductingnhalf yof the .System being-arrangedinpush-pull relation to `the magneticfcircuitson which theyaredisposed, a lead `parallel tothefbranchcircuits-and connecting said load circuit to biofth sides oflthelineand half waverectifiers in said lead disposed on each side of the load circuitconlne'ction and poledain the directionvofl-the line.

`2. A magneticamplier'as clairnedinclaim 1 wherein the control windings on each side of the load are arranged in 'the same relation with respect to the-ux induced by the load current inthe reactor windings on the conducting half-cycles--for an A C current, being wound intpushpull relation to the saidinduced flux for-a- D.C signal.

V3. Aitnagnetic amplifier-as claimed `inclaim 1 wherein `the control windingsoneach side of the load are arranged in push-pull relation with respectfto the fluxinduced bythe vload currentin the reactorvwindings on the conducting half-cyclesfor-an A.C. signal, being Vwoundin the same relation with respect-to saidinduced ux for a D.C. signal.

No references cited. 

